How can I get a shape with a emission node to be brighter in the center?
Create your text "Bar"
Duplicate it 
Extrude both text meshes
Make one skinny and one fat
Change the offset of the "skinny" one to a negative number and place it inside the "fat" one. 
Add a emission shader to the "skinny" text. Set it to 3 or so. 
On the "Fat" text add a translucent shader. 
(optional add another material to the extruded part like the picture.)